Likely E. M. Reilly & Co. London. Octagonal steel barrel with chequered walnut butt. Good, complete and functional condition.
The hammer is very strong.
Unfortunately, I cannot see any makers marks or proof marks.
I had the chamber casted just to make sure this was obsolete calibre. It is .36 calibre in rimfire.
It appears to be a gallery/parlour pistol.
The bore is pitted, likely due to being a blackpowder pistol.
Can deliver this or do an RFD transfer.